Re: Estimate of satellite vs. Land-based traffic

[Paul Donner <pdonner () cisco com>]

Jeffrey,

While technically you are correct, I would say that you probably should 
also add a category for mobile communications LAND/SEA/AIR.  The traffic 
for these will be increasing in time as vendors are starting to put 
switches and routers on-board spacecraft making applications that were 
once borderline, because of delay, more acceptable.  Depending on what 
you are doing (eg. comm between two satellite ground stations, mobile or 
stationary) the application can benefit from from reduced RTT due to 
this innovation.  One-way delay would thus be about 250ms.  This is 
greater than the generally accepted 150ms for a voice call but with good 
voice quality 250ms is not bad.  This of course is based on GEO sats. 
LEO or MEO satellites are much closer to the earth so the delay would be 
less but they present a whole host of other complexities.

While satellites will probably never come close to the volume of 
ground-based comm, they will cater to niche markets, military, mobile 
and disadvantaged users.

WRT Kevin's query, if you are concerned about a solar incident and it's 
affects on satcom, you might want to take a look at what user base (e.g. 
which mobile users and what impact loss of comm will have on what they 
are doing) is affected rather than understanding the volumes that are 
affected as this might provide a much more thorough understanding of any 
impact.  But that is merely my two cents worth.

-Donner

Jeffrey Lyon wrote:
> Kevin,
>
> Satellite transport is common mainly in areas where land based
> infrastructure is not feasible. In developed nations this is almost
> exclusively the case. Satellite latency is far too high to rely on it
> for routine communications unless used as a last resort.
>
> Best regards, Jeff
>
> On Tue, Jan 6, 2009 at 3:34 PM,  <Kevin.Smith () dca state fl us> wrote:
> > All,
> >
> > Participting in a severe solar event EXERCISE.  Can anyone give me an
> > educated guesstimate of the percentage of backbone traffic that is
> > satellite dependent vs. that which is totally land-based?
> >
> > Thanks
> >
> >
> >
> > Kevin Smith
> > Information Systems & Services
> > Department of Community Affairs
> > kevin.smith () dca state fl us  [preferred]
> > 850.922.9921  [voice]
> > 850.487.3376  [fax]
> >
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